What ISEF category is laundry detergent under?

on the science research project proposal form, it says to write the TOPIC: from the ISEF list of categories provided

my title is The Effect of the Amount of Laundry Detergent on Clean/Not Clean clothes.

so what is the ISEF topic category for that?
Thanks!
Update: i was thinking environmental sciences?
Update 2: OMG THANK YOU!
i'm trying to click best answer but the button wont show up
so yeah thanks if u need anything let me know
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